Apparatus for picking up, elevating, and discharging material



Jan. 3, 1961 F. c. HOBERG 2,966,983

APPARATUS FOR PICKING UP, ELEVATING AND DISCHARGING MATERIAL Filed Aprii 9, 1959 s Sheets-Sheet 1 2 14 FIG. 3.

Jan. 3, 1961 F. c. HOBERG APPARATUS FOR PICKING UP, ELEVATING AND DISCHARGING MATERIAL Filed April 9, 1959 5 Sheets-Sheet 2 AWE/via? F. C. HOBERG Jan. 3, 1961 APPARATUS FOR PICKING UP, ELEVATING AND DISCHARGING MATERIAL Filed April 9, 1959 3 Sheets-Sheet 3 F IG. 7.

United States Patent APPARATUS FOR PICKING UP, ELEYATING, AND DISCHARGING MATERIAL Fredrick Chresten Hoberg, 321 Pacifi'ciHighway, Crows'Nest, New South Wales, Australia Filed Apr. 9, 1959, Ser. No. 805,184

2 Claims. (Cl. 198-9) This invention relates to apparatus for picking, up, elevating and discharging material.

One of the principal objects of the invention. is to provide apparatus adapted very eificiently to dig, elevate and discharge comparatively loose heavy material, such as crushed mining products, sand or earth, the apparatus being of relatively light and economical construction. Another object of the invention is to provide such apparatus utilising buckets,v the loading action of which brings about particularly efficient use of the bucket capacity. A still further object of the invention is to provide such apparatus adapted to discharge material picked up and" elevated in a very eflicient manner, so that it may be readily received by a discharging con- Veyor, for example;

With the foregoing, and other objects in view, the invention resides broadly in apparatus for picking up, elevating and discharging material including a carrier, a plurality of buckets each mounted pivotally about a transverse axis on the carrier; means for limiting the pivotal movement of each bucket about its axis; each bucket being adapted, when advanced in a loading position, to dig and hold material; the carrier being adapted to advance the buckets sequentially along a substantially arcuate loading path and thence to and along a substantially arcuate discharging path above the level of the loading path; spring-loading means adaptedto urge each bucket to one limit of its pivotal movement; and damper means adapted to damp the pivotal movement of each bucket in opposite direction, the damper means being adapted to control the pivotal movement of each bucket moved along the arcuate loading path to restrain it against pivotal movement in one direction substantially away from leading position under the influence ,of a received load of material; the spring-loading means being adapted to move each bucket pivotally in the opposite direction when the said bucket is moved along the arcuate discharging path, so as to cause the bucket to discharge its load. Other features of the invention will: become apparent from the following description.

In' the: drawings:

Fig. 1 is a side elevational view of a bucket assembly of apparatus according to the invention,

Fig. 2 is a plan view of the bucket assembly,

Fig. 3 is a partly sectioned rear view of the bucket assembly,

Fig. 4 is a partly broken-away sectional view along line 4-4 in Fig. 3',

Fig. 5 is a sectional view of the damper device of the bucket assembly, taken along line 5'-5 on Fig. 3, and to enlarged scale,

Fig. 6 is a sectional view of the damper device taken along line 66 in Fig. 5, and r Fig. 7 is a schematic view of an arrangement of bucket assemblies operating on a rotary carrier.

Each bucket assembly ofthe apparatus includes a bucket 10, which is a fairly broad' shovel-like device having a rectangular bottom plate 11, apair of side plates 12, and a rear plate 13, which extends upwardly from the rear of the bottom plate and curves over 'to the rear, it's rearmost part inclining upwardly and rearwardly. The lower rear parts of the side plates 12' are shaped to conform to the formation of the rear plate 13. To each of the side plates 12' there is secured by bolts 14 a check plate 15, closing in the ends of the transverse concavity below the curved part of the rear plate 13 to form a housing 16,. open at bottom and rear.

Secured to the two cheek plates 15 are a pair of aligned bearings 17 for a bucket shaft 18, the ends of which are secured non-rotatably in a pair of mounting deadeyes 19 formed with bolt holes 20 whereby they may be attached to corresponding. spokes or projections of a pair of. rotary carrier wheels, indicated at 21 in Fig. 7, and mounted on a shaft indicated at 22.

Within the housing 16, there is secured upon the bucket shaft 18 a limit stop arm. 23 '(see particularly Fig. 4'), and within the upper rear part, and the lower front part, of the housing, in alignment with the limit stop arm, there are secured a pair of padded stops 24 against either of which the limit stop arm 23 may be brought by rotation of the bucket 10' about its shaft 18 in one direction or the other.. The stops 24 and limit stop arm 23 limit the rotational movement of the bucket 10 about'its shaft preferably to about l50'-l80.

, A helical bucket torsion spring 25' urges thebucket to rotate about its shaft in the direction shown by the arrow in Fig. I. This bucket spring is disposed about portion of the bucket shaft 18, within the housing, 16, one end of the spring being wound about a spring collar 26 secured to one of the bucket shaft bearings 17, the other end of the spring being wound about a spring collar 27 secured to the bucket shaft 18 by means of a split cone and clamp device indicated at 28. The end portions of the bucket spring wound about the spring collars 26' and- 27 are secured thereto by such torsion of the spring as'to cause its diameter to be diminished, and its end portions to hold very firmly to the said collars, the convolutions of these endportions of the spring lying partly in helical grooves formed about the said spring collars Within the housing 16,. these is secured to the rear plate 13 of the bucket 10 a damper bracket 29. A damperassembly, indicated generally. at 30; is" fitted upon the bucket shaft 18, within the housing 16, and is secured to the said damper bracket'29'.

Th'e damper. assembly includes a damp'e'r'barrel 31 disposed co-axially about the bucket shaft, and secured and sealed atits ends to two end covers 32 and 33, which are fitted closely about the shaft. 18, and are provided with packing rings or glands. (not shown) compressed about the shaft.

Withinthe damper barrel, there is secured to the bucket shaft 18 a vane 34, consisting of'a cylindrical hub keyed to the shaft, and a more or less sector-shaped vane arm extending therefrom, and closely approaching the internal wall of the barrel, and at its ends cl'os'ely approaching the inner ends of the end covers 32 and 33"; I

. Formed integrally within the damper barrel is a filler piece 35, which extends) inwardly into close proximity with the hub of the vane 34. Within the damper barrel, the space between one side of. the vane 34' and the filler piece 35" will be hereinafter called f the high pressure space 36,. and the space between the other side of the vane and the filler piece 35 will be hereinafter called the low pressure space 37;the high pressure space 36 being that in which fluid will be compressed by the rotational movement of the bucket about its shaft 18 in the direction opposite to that to which it is urged by the helical bucket torsion spring 25.

Within an integral projection 38 to the rear of the damper assembly 30, there is formed a cylindrical damper valve chamber 39, parallel to the bucket shaft 18. One end of this chamber is closed by a plug 40, retained in place by the end cover 32; but in the other end cover 33 there is formed a tapped hole co-axial with the damper valve chamber and of about the same diameter. Formed about and communicating with the said damper valve chamber are two annular channels 41 and 42. From the annular channel 41 a fluid passage 43 leads through the filler piece into the high pressure space 36, and from the annular channel 42 a fluid passage 44 leads through the filler piece 35 into the low pressure space 37.

Fitted closely within the damper valve chamber 39 is a sleeve 45, through which are formed a series of radial fluid passages 46 communicating with the annular channel 41, and a series of radial fluid passages 47 communicating with the annular channel 42. A passage 47a leads from within the end of the sleeve remote from plug to the annular channel 42. Within the bore of the sleeve there are formed two tapered annular grooves 48 and 49, the groove 48 communicating with the radial fluid passages 46, the other groove 49 communicating with. the radial fluid passages 47, the two grooves 48 and 49 decreasing in depth in the direction of the end cover 33.

Fitted slidably within the sleeve is a damper valve 50 of tubular form, its bore, at the end nearer to the end cover 32, being reduced to a restricted axial passage 51. Formed through the damper valve are a series of radial fluid passages 52, and a further series of radial fluid passages 53. Formed about the valve are two tapered annular grooves 54 and 55, which decrease in depth in the direction opposite to that in which the annular grooves 48 and 49 of the sleeve decrease. The groove 54 communicates with the radial fluid passages 52 of the valve, the groove communicates with the radial fluid passages 53 of the valve. When the valve is in fully retracted position, that is, moved to full extent towards the plug 40 and end cover 32, the tapered grooves 48 and 49 within the sleeve 45 become respectively aligned with the tapered grooves 54 and 55 about the valve 50. Consequently there is then opened a maximum passage from the high pressure space 36 through the fluid passage 43 to annular channel 41, and thence by way of the radial passages 46 and the aligned tapered grooves 48 and 54 and the radial passages 52 of the valve to the interior of the valve; and also from the interior of the valve through the radial passages 53 therein, the aligned tapered annular grooves 55 and 49 of valve and sleeve, the radial passages 47 of the sleeve, the annular channel 42 and the passage 44 to the low pressure space 37. When the valve is moved in opposite direction, to advanced position, the two tapered annular grooves 54 and 55 are brought out, or nearly out, of alignment with the tapered grooves 48 and 49 of the sleeve, and so the passageways from the high pressure space 37 to the interior of the valve 50, and from the interior of the valve to the low pressure space 37 are closed or nearly so.

Screwed into the end of the damper valve 50 remote from the plug 40 and end cover 32 is a tubular orifice piece 56, the bore of which is restricted at an intermediate position by an integral annular inwardly extending flange 57.

The sleeve 45 is maintained in place within the damper valve chamber 39 by an adaptor 58 screwed into the tapped hole in the end cover 33 which is co-axially aligned with the said valve chamber. The adapter 58 has an internally threaded axial hole formed therethrough, and

there is screwed into this hole a spring screw 59. The external diameter of this spring screw, at the end near to the damper valve 50, is reduced to form an annular shoulder on which is seated one end of a helical compression damper valve spring 60, the other end of this spring seating upon an annular shoulder formed about the orifice piece 56 by the reduction of the diameter of its end near to the spring screw. The damper valve spring 60 urges the damper valve 50 to retracted position, and the compression exerted by this spring may be adjusted by means of the spring screw 59, which may be locked in desired adjusted position by means of a lock nut 61.

The spring screw 59 is formed with an internally threaded axial aperture, in which there is threadedly engaged a bleed valve screw 62. Screwed into a tapped axial aperture formed from the inner end of the bleed valve screw is one end of a bleed valve stem 63 having on its other end a bleed valve 64. This bleed valve is a round-section element, its innermost end portion being of maximum diameter, the diameter of the valve decreasing towards its other end. When the damper valve 50 is in fully retracted position, the maximum-diameter portion of the bleed valve is located closely within the part of the bore of the orifice piece 56 which is restricted by the inwardly extending flange 57 thereof, so that passage through this orifice piece is closed or nearly closed. As the damper valve 50 is moved towards extended position, the annular passage between the said flange 57 and the bleed valve 64 is progressively increased, to a maximum when the damper valve is in fully extended position. The location of the bleed valve 64 may be adjusted by means of the bleed valve screw 62, which may be locked in desired adjusted position by means of an associated locknut 65. A cap 66, screwed onto the spring screw 59, covers the outer end of the said spring screw, and of the bleed valve screw 62 with its associated lock nut 65.

Suitably hydraulic fluid is introduced into the damper device by means of an appropriate inlet (not shown).

A number of buckets 10, as described, are mounted on the pair of carrier wheels 21, their shafts 18 equidistantly spaced so that, when the shaft 22 of these carrier wheels is rotated in the direction indicated by the arrow 67 in Fig. 7 the buckets are moved in a rotary path. Alternately, the buckets may be mounted at regular intervals on an endless chain type of conveyor or the like. In either case, the buckets are carried along an arcuate loading path, and subsequently along an arcuate discharging path at a high level, then returned to the loading path, and so on. The conveyor, whether of the rotary type as shown in Fig. 7, or of the endless chain or similar type, may suitably be carried by a manoeuverable boom, part of which is indicated in broken outline at 68, mounted on and extending from a vehicle (not shown) capable of traversing a path more or less parallel to the edge of a pile of material to be excavated, as indicated at 69 in Fig. 7. The vehicle also carries a discharging conveyor part of which is indicated in broken outline at 70, and which is adapted to receive and carry away material dug from the pile of material 69 by the buckets 10, and discharged by them onto the discharging conveyor. Means of any suitable character are provided for driving the shaft 22 of the carrier wheels.

In Fig. 7, the several buckets mounted on the carrier wheels are individually identified as 10A, 10B, 10C, 10D, 10E and 10F. The buckets 10A is commencing the loading path, its base more or less normal to a radius of a carrier wheel 21, and held at one limit of its rotational movement about its shaft 18 by means of its torsion spring 25. The leading edge of this bucket has met the pile 69 of material to be excavated, the bottom of the bucket inclining downwardly to the front at this stage.

Bucket 10B, at a further advanced stage, has been carried by the rotary conveyor along the loading path to dig into the pile of material to be excavated. The forces acting on this bucket as it is driven into the pile and loaded with material causes the bucket to berotated to some extent about its shaft. This rotational movement is resisted by the torsion spring 25 and more particularly by the damper device. Hydraulic fluid-inthe high pressure space 36 is forced through the passage 43 and into the annular channel 41, and thence through the radial passages 46 of the sleeve 45 through the corresponding tapered grooves 48 and 54 of the sleeve and damper valve 50 and into the interior of the valve. The damper. valve being initially held in fully retracted position by the valve spring 60, the bleed valve 64 closes or almost closes one end of the damper valve, and hydraulic fluid flows through the radial passages 53, the corresponding tapered grooves 55 and 49 of valve and sleeve, the radial passages 47, the annular channel 42 and thence, through the passage 44 to the low pressure space 37. At the same time, hydraulic fluid passes from the interior of the damper valve through the aperture 51 at one end of the valve and, the consequent fluid pressure acting on one end of the damper valve only, the damper valve advances so that the corresponding tapered grooves of valve and sleeve are brought out of alignment, and the passageway for the hydraulic fluid is reduced. Owing to the nature of the bleed valve as the damper valve advances fluid can pass bleed valve 64 into the space, within the sleeve, ahead of the damper valve, and from this space fluid bleeds by way of the restricted passage 47a into the annular channel 42 and thence to the low pressure space 37, the way through this passage 47a being constant whereas the passage for fluid past the bleed valve 64 being variable. The position at which the damper valve is arrested depends upon the pressure differential of the high and low pressure spaces 36 and 37, the elastic modulus and initial compression of valve spring 60, and the profile characteristics and adjustment of bleed valve 64. The parts are so made and adjusted that the speed of rotation of a bucket about its shaft during the loading stages and until it reaches the limit of its rotational movement will be nearly the same as that of the carrier wheels. Consequently, bucket B is rotated about its shaft sufficiently to bring it to such position that its bottom is more or less horizontal; and bucket 10C, at a further advanced stage of the loading, is also substantially horizontal, the rotational movement of the bucket about its shaft corresponding to the rotation of the carrier wheels. Buckets 10B and 100, then, as shown in Fig. 7, are in optimum digging position, and bucket 10D, at a further advanced stage, and lifted clear of the pile of material being excavated, is also more or less horizontally disposed, and so is at or about the optimum elevating position. Bucket 10D is also at or about the limit of its rotational movement about its shaft against the action of its torsion spring; and so, with further rotation of the carrier wheels, cannot continue to rotate in the same direction about its shaft.

Bucket E has been brought to a further advanced position and is at about the commencement of the discharging path. The centre of gravity of the loaded bucket being brought, by rotation of the carrier wheels, towards a position above the bucket shaft, the torsion spring of the bucket assembly is able to act to move the bucket back to original position, in the direction indicated by arrows 71 and 72 in Fig. 7, in relation to the buckets 10E and 10F. Now, as the damper device has a differential action, it will offer little opposition to this spring action. Pressure in the spaces 36 and 37 having been equalised, the damper valve will have returned to retracted position under the action of its spring 60, and consequently fluid may flow freely from the space 37 within the damper device through pass-age 44 and annular channel 42, through radial passages 47, aligned tapered grooves 49 and 55 and radial passages 53 to the interior of the damper valve, through radial passages 52 aligned tapered grooves 54 and 48 and radial passages 46 to the annular channels 41 and thence through the passage 43' to the space 38. Conse quently the buckets, on the discharge path, are thrown fairly violently over to eject their contents. Emptied bucket 10F is returning. rapidly towards the limit of. its rotational movement about its shaft under the influence of. its torsion spring, to take up a position similar to that of bucket 10A.

In order to prevent premature unloading of a bucket which may be only partly filled, the force exerted by the bucket torsion spring 25 must be such as to support somewhat less than half the anticipated load in addition to the moment of the weight of the bucket about its shaft. It will be appreciated that the forces which tend to depress a bucket during the loading operations depend firstly upon the density of the material being loaded and its relative looseness in the pile which are characteristics of a given pile of material, and secondly upon the speed at which the bucket is moving, the speed at which the whole machine is moving and the depth of out which the buckets are taking, all of which are under the control of the operator. The forces tending to keep the bucket horizontal during loading are, to a minor extent, the action of the bucket torsion spring, and to the major extent, the action of the damper device. The strength and elastic modulus of the spring are primarily determined to satisfy conditions before and after the loading operations; and the damper may be designed and adjusted to suit the particular conditions under which the apparatus is to be operated.

It may be found necessary to compensate for variations in the performance of the damper device consequent upon changes in the viscosity of the hydraulic fluid due to changes in the ambient temperature. Small viscosity changes may be compensated for by variations in the speed of carrier wheels. Larger changes in viscosity may be compensated for by adjustment of the cross-sectional area of the passage 47a from the space ahead of the damper valve to the annular channel 42 by means of a needle valve (not shown) associated with and adapted to be moved to close the passage 47a. This needle valve may be controlled by a solenoid device mounted upon the damper and incorporated in an electrical circuit by brushes and collector rings concentric with the carrier wheel shaft 22. If the passage 47a is reduced the pressure in the space ahead of the damper valve 50 increases, and, for a given difference in pressure between the high and low pressure spaces 36 and 37, the damper valve reaches equilibrium with a lesser advance, and thus with a greater passageway for the hydraulic fluid between the high and low pressure spaces. Thus, a faster speed of rotation of each bucket about its shaft occurs. Since the movement of the solenoid controlled needle valve is proportional to a function of the electric current passing through the solenoid, by suitably adjusting this current before excavation is commenced the desired speed of rotation of the buckets about their shafts may be obtained irrespective of the viscosity of the hydraulic fluid due to the ambient temperature.

I claim:

1. Apparatus for picking up, elevating and discharging material including a carrier; a plurality of buckets each mounted pivotally about a transverse axis on the carrier; means for limiting the pivotal movement of each bucket about its axis; each bucket being adapted, when advanced in a loading position, to dig and hold material; the carrier being adapted to advance the buckets sequentially along a substantially arcuate loading path and thence to and along a substantially arcuate discharging path above the level of the loading path; a damper adapted to control the pivotal movement of each bucket moved along the loading path to restrain its pivotal movement in one direction substantially away from leading position under the influence of a received load of material; and springloading means adapted to move each bucket pivotally in the opposite direction partly to counterbalance the bucket in its passage along the loading path and so to move the bucket pivotally during its passage along the discharging path as to cause it to discharge its load.

2. Apparatus for picking up, elevating and discharging material according to claim 1 wherein the carrier is a rotary conveyor; and the buckets are mounted upon transverse shafts secured in equidistant relationship to the rotary conveyor and parallel to the axis thereof.

' References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Germany Nov. 5, 1927 

